Medical imaging has shown rapid technological advancement in image resolution and quality, ease-of-use, and cost effectiveness over the past decade. In the dental industry, these advancements have led to reductions in oral diseases, such as tooth decay and tooth misalignment. Currently, the main imaging modalities in dentistry are two-dimensional (2D) plane x-ray and x-ray computed tomography (CT). While these modalities are well-suited for hard tissue (e.g., bone and teeth), they have limited utility for soft tissue (e.g., gingiva). Characterization of soft tissue is crucial given that gum inflammation (gingivitis) and gum disease (periodontitis) are highly prevalent, affecting half of adults over the age of 30 years in the U.S. Numerous studies have shown that poor gum health can lead to early tooth loss and decay and is associated with a variety of systemic health issues including heart disease, diabetes, and stroke. Because the disease is limited to the soft-tissue structures, it is often not clinically diagnosable via x-ray images. The only way to evaluate these structures is by probing the gum line using a metal probe to check for the periodontal pocket depth, as is done at a routine dental visit. However, this technique is very painful for patients, has poor sensitivity and specificity, and is susceptible to high inter-practitioner variability.
Medical ultrasound imaging is an imaging technique that uses acoustic waves generally on the order of megahertz (MHz) in frequency to image structures in the body. In contrast to x-rays, ultrasound waves are attenuated and reflected differentially by subtle heterogeneities in soft tissues. This makes ultrasound ideal for soft tissue imaging. Today, ultrasound continues to be a major imaging modality used in the medical field to examine many organs including the heart, liver, kidneys, and male and female reproductive organs. However, dental practitioners have yet to adopt oral cavity ultrasound despite its high potential. This is due in part to limitations in technology to develop an ultrasound probe small enough to be used in the oral cavity but also the need for supporting hardware and software to facilitate the acquisition of data that are easy for the practitioner to interpret and utilize. Described herein are systems and methods employing ultrasound imaging techniques in order to image soft tissue in the oral cavity for tracking the progression of diseases, such as periodontitis, and other applications. A high-frequency ultrasound transducer integrated with an actuation device allows for consistent image acquisition, which may result in high-resolution, three-dimensional (3D) ultrasound images of oral soft tissue of the oral cavity.
In one general aspect, an ultrasound oral imaging instrument is disclosed. The ultrasound oral imaging instrument includes an actuator couplable to an ultrasound probe and a control circuit. The actuator is configured to move the ultrasound probe between a first position and a second position. The control circuit is couplable to the ultrasonic transducer of the ultrasound probe and coupled to the actuator. The control circuit is configured to cause the ultrasonic transducer to emit ultrasound pulses through the ultrasound probe and cause the actuator to move the ultrasound probe between the first position and the second position as the ultrasound probe emits the ultrasound pulses.
In another general aspect, a method for obtaining oral images via an ultrasound oral imaging instrument is disclosed. The method includes applying an acoustic coupler between a gingival tissue of a patient and an ultrasound probe of the ultrasound oral imaging instrument; moving the ultrasound probe along the gingival tissue, the ultrasound probe comprising a ultrasonic transducer configured to emit an ultrasonic pulse; capturing a plurality of 2D images via the ultrasound probe as the ultrasound probe is moved along the gingival tissue; and reconstructing the plurality of 2D images into a 3D image of the gingival tissue.
The features of various aspects are set forth with particularity in the appended claims. The various aspects, however, both as to organization and methods of operation, together with further objects and advantages thereof, may best be understood by reference to the following description, taken in conjunction with the accompanying drawings as follows.
Certain aspects will now be described to provide an overall understanding of the principles of the structure, function, manufacture, and use of the devices and methods disclosed herein. One or more examples of these aspects are illustrated in the accompanying drawings. Those of ordinary skill in the art will understand that the devices and methods specifically described herein and illustrated in the accompanying drawings are non-limiting examples aspects and that the scope of the various aspects is defined solely by the claims. The features illustrated or described in connection with one aspect may be combined with the features of other aspects. Such modifications and variations are intended to be included within the scope of the claims. Furthermore, unless otherwise indicated, the terms and expressions employed herein have been chosen for the purpose of describing the illustrative aspects for the convenience of the reader and are not to limit the scope thereof.
In many dental imaging applications, x-ray imaging or other x-ray-based imaging modalities are generally used. These imaging modalities are ideal for imaging hard structures in the mouth such as teeth or the maxillary bone. However, they are poorly suited for imaging soft tissue. One advantage of the systems and methods utilizing an ultrasound oral imaging instrument that are described herein is that ultrasound imaging has the capability of producing very high-resolution images of soft tissue in the oral cavity, due in part to the short acoustic signal path. A short acoustic signal path reduces the effects of acoustic attenuation, which in turn allows high frequency (i.e., >10 MHz, generally) sound waves to be utilized. Accordingly, ultrasound imaging is highly advantageous for imaging soft oral tissue.
Further, 3D ultrasound imaging applications, in general, require an ultrasound imaging probe that is built to acquire 3D images without moving the probe. However, these 3D imaging probes are generally relatively expensive and also generally require a relatively large amount of operating space. Another advantage of the systems and methods utilizing an ultrasound oral imaging instrument that are described herein is that 3D images can be reconstructed from 2D ultrasound images acquired via an ultrasound imaging instrument. By reconstructing 3D images from 2D images, the presently described system obviates the need for specialized 3D imaging probes to acquire 3D images.
The ultrasound probe 108 can include an ultrasonic transducer 402 that is configured to produce ultrasound waves or pulses that propagate through and are reflected by the tissue against which the ultrasound probe 108 is situated. The ultrasound probe 108 then receives the reflected sound waves. Images of tissues or structures underlying the surface of the tissue can be constructed by evaluating the reflected sound signals, which can correspond to the different acoustic impedances of the underlying materials. For example, the length of time between when a sound signal is initially transmitted and when the corresponding reflected sound signal is received (i.e., the time-of-flight of the sound signal) can be utilized to determine the depth of a structure from which the sound signal was reflected. In one aspect, the ultrasound probe 108 is driven at a frequency between 10-65 MHz. In another aspect, the ultrasound probe 108 is driven at a frequency of at least 20 MHz. In some aspects, the ultrasound probe 108 can include an ultrasonic transducer 402 comprising one or more piezoelectric elements 403 that vibrate according to a drive signal provided by an electrical connection 404. The piezoelectric elements 403 can be arranged in a number of different configurations, including being arranged in stacks or phased arrays (e.g., linear, rectangular, annular, or circular arrays of piezoelectric elements 403). In some aspects, the piezoelectric elements 403 in the ultrasonic transducer 402 may vibrate in- or out-of-phase with one another. In aspects where the piezoelectric elements 403 are arranged in a stacked configuration, the phase differences between the piezoelectric elements 403 can change the amplitude of the ultrasound pulses generated by the ultrasonic transducer 402, for example. In aspects where the piezoelectric elements 403 are arranged in phased arrays, the phase differences between the piezoelectric elements 403 can cause the ultrasound pulses generated by the ultrasonic transducer 402 to be emitted at different times and/or in different directions. In some aspects, the drive signal is provided via an onboard control circuit 110, whereas in other aspects the drive signal can be provided by an external generator to which the ultrasound oral imaging instrument 100 is connectable. As the piezoelectric elements 403 vibrate, the ultrasonic transducer 402 can transmit pulsed sound waves through an opening 305 in the ultrasound probe 108 to any tissue that it situated thereagainst. In one aspect, the ultrasound probe 108 can further include an acoustic lens and/or an acoustic matching layer (e.g., a quarter wavelength acoustic matching layer) situated over the opening 305. An acoustic matching layer and/or an acoustic lens can be beneficial in order to improve transmission of ultrasound pulses to any tissue that is situated thereagainst.
In various aspects, the actuator 105 can be configured to impart linear and/or rotational movement on the ultrasound probe 108 through the shaft 102 coupled to the actuator 105. In some aspects, the ultrasound oral imaging instrument 100 can include multiple actuators 105 for actuating the ultrasound probe 108 by and/or about multiple axes. In the depicted aspect, the actuator 105 is a linear actuator that is configured to actuate the ultrasound probe 108, the shaft 102, and/or the mount 101 along the longitudinal axis 120 of the shaft 102 between a first or proximal position and a second or distal position. The movement imparted by the actuator 105 can include unidirectional or reciprocating (i.e., oscillating) movement. The first position, the second position, any positions in between the first and second positions, and/or the rate at which the actuator 105 moves the ultrasound probe 108 or the shaft 102 between two positions can be predetermined, set by a control circuit 110 coupled to the actuator 105, or set by a user via user controls 104. In various aspects, the actuator(s) 105 can be configured to impart stepped or continuous motion. For example, the actuator(s) 105 can include a stepper motor, servo motor, piezo motor, pneumatic actuator, and so on. In one aspect, the actuator 105 is configured to impart motion that is precise to a sub-millimeter scale (e.g., the actuator 105 can include a step motor having sub-millimeter step sizes). The actuator 105 can be configured to impart a range of motion (i.e., the distance between the first position and the second position) on the ultrasound probe 108, the shaft 102, and/or the mount 101 of several centimeters or more, for example. The actuator 105 can also be configured to drive the ultrasound probe 108, the shaft 102, and/or the mount 101 at a rate of one cm/s or more, for example.
The ultrasound probe 108 can be configured to emit the sound pulses in different orientations or at a range of angles relative to the direction in which the ultrasound probe 108 is actuated. The angle at which the sound pulses are emitted by the ultrasound probe 108 can be controlled according to the orientation of the ultrasonic transducer 402 within the ultrasonic probe 108, utilizing phased arrays of piezoelectric elements 403, and so on. For example, in the aspect depicted in
The ultrasound oral imaging instrument 100 further includes a control circuit 110 that is coupled to the actuator 105 and/or the ultrasound probe 108. The control circuit 110 can include combinations of hardware, firmware, and/or software components for performing the recited functions. Further, the ultrasound oral imaging instrument 100 can include a power source coupled to the control circuit 110 for powering and/or providing signals for driving various components of the ultrasound oral imaging instrument 100. In one aspect, the control circuit 110 is configured to provide a drive signal (e.g., an AC electrical signal) to the ultrasonic transducer 402 to cause the ultrasonic transducer 402 to emit ultrasound pulses. In one aspect, the control circuit 110 is coupled to the actuator 105 and is configured to control the actuator 105 in order to cause the actuator 105 to move the ultrasound probe 108 at a known rate as the ultrasound probe 108 emits the ultrasound pulses. As the ultrasound probe 108 moves, it sends and receives ultrasound pulses that can be utilized to construct 2D images of the tissue. Each of these images is a 2D “slice” of the tissue being visualized. Further, because the ultrasound probe 108 is moving between known positions at a known rate, the ultrasound probe 108 is thus taking multiple 2D slices of the underlying tissue at different positions (which are known because the ultrasound probe 108 is moving between known positions at a known rate). Accordingly, the 2D slices can be arranged according to their positions, and then 3D images of the underlying tissue can be constructed from the 2D slices, as is described in more detail below.
In one aspect, the ultrasound oral imaging instrument 100 can include controls 104 for controlling various functions or modes of the ultrasound oral imaging instrument 100. For example, the controls 104 can be coupled to the control circuit 110 and cause the ultrasound oral imaging instrument 100 to turn on and off, determine the direction and/or speed of movement of the ultrasound probe 108, determine when ultrasound data are being acquired, and so on. For example, the controls 104 can include buttons that cause the ultrasound probe 108 to move forward quickly, forward slowly, reverse slowly, and reverse quickly. In other aspects, the ultrasound oral imaging instrument 100 does not include any controls 104 and instead the control circuit 110 controls the functions of the ultrasound oral imaging instrument 100 according to predetermined or preprogrammed instructions. In some aspects, the control circuit 110 can be configured to control the ultrasound oral imaging instrument 100 according to instructions that are transmitted to, loaded onto, or otherwise provided to the ultrasound oral imaging instrument 100 from an external computer or electronic device.
In various aspects, the ultrasound oral imaging instrument 100 can be configured to receive power and/or instructions from an external source, such as a generator, a computer, or an electronic device, as described above. In such aspects, the ultrasound oral imaging instrument 100 can include various connectors for receiving power and/or data from the external source. Such connectors can include, for example, various wired connectors, such as USB Type-C connector or a power cord, or wireless connectors, such as a Bluetooth transceiver.
The ultrasonic oral imaging system further includes an image reconstruction module 809 that is communicably coupled to the ultrasound probe 808 (e.g., via the electrical connection 404). In one aspect, the image reconstruction module 809 can receive the ultrasound signal data from the ultrasound probe 808, construct 2D images from the signal data, determine the position corresponding to each of the 2D images, and then construct 3D images from the 2D images utilizing a variety of 3D reconstruction algorithms. In one aspect, the image reconstruction module 809 can include, for example, an image processing program, which may be a custom image processing program written in a variety of computer languages, such as Python, C/C++, C#, Java, or JavaScript, for example. The image reconstruction module 809 can also or alternatively include a variety of particular algorithms, such as a volume rendering algorithm or a machine learning or deep learning algorithm. In some aspects, the image reconstruction module 809 is executed by a control circuit 110 of the ultrasound oral imaging instrument 100. In other aspects, the image reconstruction module 809 is executed by an external computer or electronic device to which the ultrasound oral imaging instrument 100 is communicably connectable. For example, the ultrasound oral imaging instrument 100 can store the ultrasound signal data in an onboard memory, which can then be downloaded to an external computer executing the image reconstruction module 809 from the ultrasound oral imaging instrument 100. As another example, the ultrasound oral imaging instrument 100 can transmit the captured ultrasound signal data to an external computer executing the image reconstruction module 809 via a wired or wireless connection. In some aspects, feedback from the image reconstruction module 809 can control various functions of the ultrasound probe 808 and/or the linear actuator controls 804. For example, if the image reconstruction module 809 determines that there was an error with obtaining a particular image or set of images, feedback from the image reconstruction module 809 can cause the ultrasound probe 808 to reactive, alter the frequency at which the ultrasound pulses are emitted, alter the orientation at which the ultrasound pulses are emitted, and so on. As another example, if the image reconstruction module 809 determines that there was an error with obtaining a particular image or set of images, feedback from the image reconstruction module 809 can cause the linear actuator controls 804 to move the ultrasound probe 108 back over the target area to be imaged, change a speed at which the linear actuator 806 drives the ultrasound probe 808, change the range of motion that the ultrasound probe 808 to cover a larger or small area of tissue to be imaged, and so on.
As discussed above, in some aspects the electronic components of the ultrasound oral imaging instrument 100 can be integral to the ultrasound oral imaging instrument 100 (i.e., enclosed within the housing 106). In other aspects, various electronic components can be positioned within a generator or an external control device 502 to which the ultrasound oral imaging instrument 100 is connectable, as depicted in
The ultrasound oral imaging instrument 100 described herein has many relevant oral healthcare applications. As noted above, the ultrasound oral imaging instrument 100 can be utilized to image soft oral tissue. In one example described below in connection with
A 3D reconstruction of the periodontal pocket 703 around a tooth 705 can then be visualized according to 2D slices constructed from ultrasound data indicating the different acoustic characteristics of the bone 706, teeth 705, and/or surrounding gingival tissue 708, as described above. In some aspects, the ultrasound oral imaging instrument 100 can be moved along the gingival surface 702 to visualize an extended area or the ultrasound oral imaging instrument 100 can be held in place or substantially held in place in order to visualize a precise location of the gingival tissue 708. In various aspects, the images captured via the ultrasound probe 108 can be supplied either in real time (i.e., at the time of image acquisition) or at a later time (e.g., stored in a memory of the ultrasound oral imaging instrument 100, an external control device 502, and/or a computer to which the ultrasound oral imaging instrument 100 is communicably connected for playback at a later time).
In other aspects, the ultrasound oral imaging instrument 100 can be fixedly held in position relative to the mouth being visualized, rather than being a handheld instrument as indicated in
As another example,
As used in any aspect herein, the term “control circuit” may refer to, for example, hardwired circuitry, programmable circuitry (e.g., a computer processor including one or more individual instruction processing cores, processing unit, processor, microcontroller, microcontroller unit, controller, digital signal processor (DSP), programmable logic device (PLD), programmable logic array (PLA), or field programmable gate array (FPGA)), state machine circuitry, firmware that stores instructions executed by programmable circuitry, and any combination thereof. The control circuit may, collectively or individually, be embodied as circuitry that forms part of a larger system, for example, an integrated circuit (IC), an application-specific integrated circuit (ASIC), a system on-chip (SoC), desktop computers, laptop computers, tablet computers, servers, smart phones, etc. Accordingly, as used herein “control circuit” includes, but is not limited to, electrical circuitry having at least one discrete electrical circuit, electrical circuitry having at least one integrated circuit, electrical circuitry having at least one application specific integrated circuit, electrical circuitry forming a general purpose computing device configured by a computer program (e.g., a general purpose computer configured by a computer program which at least partially carries out processes and/or devices described herein, or a microprocessor configured by a computer program which at least partially carries out processes and/or devices described herein), electrical circuitry forming a memory device (e.g., forms of random access memory or data storage, e.g., a hard drive), and/or electrical circuitry forming a communications device (e.g., a modem, communications switch, or optical-electrical equipment). Those having skill in the art will recognize that the subject matter described herein may be implemented in an analog or digital fashion or some combination thereof.
As used in any aspect herein, the terms “component,” “system,” “module,” and the like can refer to a computer-related entity, either hardware, a combination of hardware and software, software, or software in execution.
One or more components may be referred to herein as “configured to,” “configurable to,” “operable/operative to,” “adapted/adaptable,” “able to,” “conformable/conformed to,” etc. Those skilled in the art will recognize that “configured to” can generally encompass active-state components, inactive-state components, and/or standby-state components, unless context requires otherwise.
The terms “proximal” and “distal” are used herein with reference to a clinician manipulating the ultrasound oral imaging instrument. The term “proximal” refers to the portion closest to the clinician, and the term “distal” refers to the portion located away from the clinician. It will be further appreciated that, for convenience and clarity, spatial terms such as “vertical,” “horizontal,” “up,” and “down” may be used herein with respect to the drawings. However, the ultrasound oral imaging instruments are used in many orientations and positions, and these terms are not intended to be limiting and/or absolute.
Those skilled in the art will recognize that, in general, terms used herein, and especially in the appended claims (e.g., bodies of the appended claims), are generally intended as “open” terms (e.g., the term “including” should be interpreted as “including but not limited to,” the term “having” should be interpreted as “having at least,” the term “includes” should be interpreted as “includes but is not limited to,” etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases “at least one” and “one or more” to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles “a” or “an” limits any particular claim containing such introduced claim recitation to claims containing only one such recitation, even when the same claim includes the introductory phrases “one or more” or “at least one” and indefinite articles such as “a” or “an” (e.g., “a” and/or “an” should typically be interpreted to mean “at least one” or “one or more”); the same holds true for the use of definite articles used to introduce claim recitations.
In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (e.g., the bare recitation of “two recitations,” without other modifiers, typically means at least two recitations, or two or more recitations). Furthermore, in those instances where a convention analogous to “at least one of A, B, and C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B, and C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). In those instances where a convention analogous to “at least one of A, B, or C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B, or C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). It will be further understood by those within the art that typically a disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms unless context dictates otherwise. For example, the phrase “A or B” will be typically understood to include the possibilities of “A” or “B” or “A and B.”
It is worthy to note that any reference to “one aspect,” “an aspect,” “an exemplification,” “one exemplification,” and the like means that a particular feature, structure, or characteristic described in connection with the aspect is included in at least one aspect. Thus, appearances of the phrases “in one aspect,” “in an aspect,” “in an exemplification,” and “in one exemplification” in various places throughout the specification are not necessarily all referring to the same aspect. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more aspects.
In summary, numerous benefits have been described that result from employing the concepts described herein. The foregoing description of the one or more forms has been presented for purposes of illustration and description. It is not intended to be exhaustive or limiting to the precise form disclosed. Modifications or variations are possible in light of the above teachings. The one or more forms were chosen and described in order to illustrate principles and practical application to thereby enable one of ordinary skill in the art to utilize the various forms and with various modifications as are suited to the particular use contemplated. It is intended that the claims submitted herewith define the overall scope.
The present application claims priority under 35 U.S.C. § 119(e) to U.S. Provisional Patent Application No. 62/584,315, titled SYSTEM FOR ACQUISITION OF ORAL CAVITY ULTRASOUND IMAGES, filed on Nov. 10, 2017, the disclosure of which is herein incorporated by reference in its entirety.
Number | Date | Country | |
---|---|---|---|
62584315 | Nov 2017 | US |